.section .data

helloworld:
    .ascii "hello world\n\0"

.section .text
.globl  _start
_start:
    mov     $helloworld, %rdi
    call    printf

    mov     $0, %rdi
    call    exit

# as helloworld_lib.s -o helloworld_lib.o
# ld -I /lib64/ld-linux-x86-64.so.2 -o helloworld_lib helloworld_lib.o -lc

# -lc : 使用库c
# -I  : 加载链接库，并链接到程序
